Self-esteem is a fraud perpetrated at intolerable cost to the normal majority. Excellence will always be with us. You cannot and should not bring everyone else down to feel better.
In my lifetime I have worked with excellent professionals who were either dyslexic or otherwise unable to spell even the most ordinary often used words. They did not focus on redefining normal. They simply excelled at what they could do and allowed someone else to deal with the spelling. In other words, they accepted their limitations, and did not attempt to persecute others to appear normal.
Spelling is not culture. Homer is culture, but he was blind and composed hundreds of years before the Greeks had writing. For both reasons he did not write. Yet the Odyssey is culture.
English spelling was as-you-like it until around 1780, when popularity of Johnson's dictionary standardized it. But Shakespeare was cultured.
Spelling is a code, a method for conveying information, nothing more. It did not come down on golden tablets, nor was it a work of genius like the Declaration of Independence. Our spelling just happened by accident, and looks that way.
A code should be efficient. Ours is not, and should be fixed.
As for dumbing down, that would not be possible. Our spelling is as dumb as it gets. (Imagine pronouncing these words as they are written: write, know, have, done, thought, though, through, cough, tough, gnaw, knight, night...)